Arrangement for converting direct current into alternating current by means of electric vacuum valves



H. EGG 1,788,426

Jan. 13, 1931.

ARRANGEMENT FOR CONVERTING DIRECT CURRENT INTO ALTERNATING CURRENT BY MEANS OF ELECTRIC VACUUM VALVES Filed Dec. 14, 1928 AIIII I 3 3 5c 'h W 3 H a D m-n R R2 11 v, 4 7

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w/' g i .Patented Jan 13, 1931 "UNITED PATENT i imnrarn viv Q's zualcn, sWITzEnLANn, AssIe -oa To masoninnnrnrmK onnmxoiv, oronnLIKQNQNEAn zUR-IoH, SWITZERLAND, A CORPORATION oFrHE,

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' ARRANGEMENT FOR. 'ooivvnnrmefmnnc'r CURRENT nrro ALrEnNArmG cunnnirr BY MEANS on nLncrrnIo VACUUM vALvEs Application filed December 14, 1923, Serial No.

This invention relates to the conversion oi direct current into alternating current by eans o e ectric vacuum va v s-v "l T e i ention has more. particula rat rence to an arrangement wherein two or more vacuum valvesare rendered conductiveby and with the negative pole of the direct current source and its anode connected with a point of the primary winding of a trans former which is momentarily at a higher potential than the anode of said first valve.

In order that at the'moment of ionization of the valve having the higher anodev poten-- tial a relatively largercurrent may be pro duced for quenching the valve having the lower anode potential which does not pass through the primary Winding of the transformer, the arrangements above mentioned may include condensers which are inserted in parallel with the vacuum valves and are also adapted to influence thetemporary in; crease and decrease of current in sa d primary wind ng at the moment of ionization and of quenching respectively of'the valves.

One object of the invention is to produce Q quenching of said valves without the necessity of providing special quenching conconjunction with the attached drawing on which Fig. 1 shows diagrammatically one Jarrangement for converting direct currentinto alternating current. I

F g- 2 sh i g amma ical y a mod fied;

lat-ed switch,

former T is provided with a third winding,

326,050, and in- Switzerland December 18, 1927-.

arrangement provided with safety out out devices.

Referring 120' Fig. 1, denotes the main transformer, with the primary winding P and secondary wlnding S, V and V the vacuum valves, A and A the1r main anodes,

'Z, and Z their ionizing anodes, K andK,

theircathodes, Q, the source of direct current and D a choke. Furthermore, C and C de note the condensers which are connected in parallel with the vacuum valves, each being connected to a separate winding of an aux iliary transformer T. R and R are resistances by means of whichthe condenser cur rents can be rendered aperiodic; Assuming that, at a given moment, the valve V is con ductive and the valve V is non-conductive, the condenser 0 is then short-circuited through the valve V whilst the condenser C is charged to the potential of the anode A Ifnow the valve V be energized through the ionizing anode Z and thereby rendered con-v ductive, the condenser C will discharge through the valve V and this discharge cur rent induces (through the transformer T") in the circuit of the condenser C a'quenching current which quenches the valve V On the potentialrising at the anode A the condenser C becomes charged. It now the valve V be energized through the ionizing anode Z the operations described With'reference to V are repeated. in the valve V whilst the valve V is now quenched by the current quenching induced'in the circuit of the condenser C The rhythmic ionizing of the valves V and V is thus at the same time accompanied by a rhythmic quenching of the valves V and V This arrangement canalso be employed for interrupting the current conversion, which interruption can be effected automatically on a certain maximum current being exceeded, or on the direct current suddenly rising above a permissible limit as the result of a short circuit; or it may be effected by ahand-oper- With this object, the transwhich is traversed by the direct current to be converted, a portion of same being short-circu ted through a switch which s opened,

either by the direct Current to be converted, when a given maximum is exceeded, or by an auxiliary circuit which is closed by a hand switch. Opening of this switch, suddenly increases the value of the ampere-turns of the direct current winding of the transformer T, thereby inducing, in the circuits of both the condensers in parallel with the valves, a quenching voltage, so that the valve which is conductive at the moment is quenched. The case is the same when the direct current suddenly rises as the result of a short-ci'cuit. In order also to interrupt the ionization and prevent a fresh ionization, there is connected in the direct current circuit a second auxiliary transformer, the direct current winding of which is also partially short-circuited through the aforesaid switch. The secondary current induced in this second auxiliary transformer by a rapid change of field quenches an auxiliary vacuum valve disposed in the common return lead of the ionizing current serving for the rhythmic ionization of the n'iain vacuum valves, so that such rhythmic ionization is interrupted. A typical embodimen of this arrangement is shown in Fig. 2 in which the same parts are denoted by the same refe characters as in Fig. 1. T is the aux transformer with three windii the third windin being traversed by direct current whilst the other two are connected to the condensers C and C T is a secondary auxiliary transformer, one winding of which is traversed by direct current, whilst the other is connected to a condenser G hich serves to quench an auxiliary vacuum valve V. l and 2 are ionizing current leads, whilst 8 the common return lead, in which is interposed the auxiliary vacuum valve V having an anode A cathode K and an ionizing anode Z Ordinarily, this auxiliary valve is maintained in a conductive state by a source Q1 of direct current.

If the value of direct current ampere-turns in the auxiliary transformers T and T is suddenly increased, whether by a short-circuit, or by opening the switch Sch by means of a direct current solenoid $39 or by a trip solenoid S19 (by actuating a hand switch H), voltages or currents are induced in the secondary windings of these transformers and quench the main valves V V and the auxiliary valve V through the condensers C C C D is a choked coil, the value of which is such that neither any appreciable portion of the ionizing current impulse nor of quenching current impulse can pass therethrough.

In the rhythmic quenching of the main valves, although a voltage is also induced in the direct current winding of the auxiliary transformer T; nevertheless, since at such moment the quenching circuit is short circuited through the conductive vacuum valve,

the greater portion of the induced energy w1ll be thereby absorbed, especially slnce the lnductances of the main transformer T and the choke coil D are operative in the direct current circuit.

I claim 1. That improvement in the art of converting direct current into alternating current by means of two electric vacuum valves each alternately submitted to regular ionization which sets up a back electromotive force between the cathode and the anode of said other valve to quench said other valve and to interrupt the conductivity thereof which consists in inserting a condenser in parallel with each of said valves and coupling the condenser circuits together so that the discharge current of one condenser at the moment of ionization of said vacuum valve in parallel therewith sets up a quenching current in the condenser circuit of said other vacuum valve.

2. That improvement in the art of converting direct current into alternating current by means of two electric vacuum valves each alternately submitted to regular ionization which sets up a back electromotive force between the cathode and the anode of said other valve to quench said other valve and to interrupt the conductivity thereof which consists in inserting a condenser in parallel with each of said valves and utilizing the discharge current of one condenser at the moment of ionization of said vacuum valve in parallel therewith to induce a quenching current for said other vacuum valve in the condenser circuit of said other vacuum valve.

3. An arrangement for converting direct current into alternating current which comprises a transformer having a primary and a secondary winding, a source of direct current having its positive pole connected to the mid point of said primary winding, a vacuum valve having its anode connected to one end of said primary winding, a second vacuum valve having its anode connected to the opposite end of said primary winding, means connecting the cathode of each of said vacuum valves to the negative pole of said source, separate ionizing anodes for each of said valves, a condenser connected in parallel with said first vacuum valve, a condenser connected in parallel with said second vacuum valve and inductive means coupling said condenser circuits.

4. An arrangement for converting direct current into alternating current which comprises a transformer having a primary anda secondary winding, a source of direct current having its positive pole connected to the mid point of said primary winding, a vacuum valve having its anode connected to one end of said primary winding, a second vacuum valve having its anode connected to the Opposite end of said primary winding, means connecting the cathode of each of said vacuum valves to the negative ole of said source,separate ionizing anodes or each of said valves, a condenser" connected in parallel with said first vacuum valve, a condenser connected in parallel with said second vacuum valve and an auxiliary transformer having one winding current into alternating current which com prises a transformer having a primary and a secondary winding, a source of direct current having its positive pole connected to the mid point of said primary winding, a vacuum valve having its anode connected to one end of said primary winding, a second vacuum valve having its anode connected to the opposite end of said primary winding, means connecting the cathode of each of said vacuum valves to the negative pole of said source, separate ionizing anodes for each of said valves, a condenser connected in parellel with said first vacuum valve, a condenser connected in parellel with said second vacuum valve and an auxiliary transformer having one winding connected in series with one condenser, another winding connected in series with said other condenser and a third winding connected in series with said source of direct current and adapted onpassage of an overload current through said third winding to induce a quenching current in each of said condenser circuits for the simultaneous quenching of said vacuum valves.

6. An arrangement for converting direct current into alternating current which comprises a transformer having a primary and a secondary winding, a source of direct current having its positive pole connected to the mid point of said primary winding, a vacuum valve having its anode connected to one end of said primary winding, a second vacuumvalve having its anode connected to the opposite end of said primary winding, means connecting the cathode of each of said vacuum valves to the negative pole of said source, separate ionizing anodes for each of said valves, a condenser connected in parallel with said first vacuum valve, a condenser connected in parallel with said second vacuum valve, an. auxiliary transformer having one winding connected in series with one condenser, another winding in series with said other condenser, and a third winding in series with said source of direct current and means to increase the ampere turns of said third winding to induce in said other windings a quenching current adapted to quench said valves.

7. An arrangement for converting direct current into alternating current which comprises a transformer having aprimary and a secondary winding, a source'of direct current having its positive pole connected to he mid point ref-sai primary winding, s c m veh vingvits anode c nnec ed to one end of Said prim ry winding, a second a uum valve h. ingxits anode. connected to. thef' 'opposite end of ,,sai d primary winding,

mea s connecti g the. ca hode o each of; said vacuum valves to T'the negative pole of; said source separate ionizing anodes for each ofsaid valves a condenser connected in parah lel with saidfirst vacuum va1ve,-.a condenser connected inparallel with said second vac.- uum; -:valve, an auxiliary transformer hav ingzone winding connected in series with one condenser, another-winding in series with said other condenser, anda third winding in series-with said source of direct current and means responsive to an overload current through said source of direct currentto increase the ampere turns of said thlrd Winding to induce insaid other windings a quenchingicurrent adapted to quench said valves. W

An arrangement for converting direct" current into alternating. current which comprises a transformer havlng a primary and a secondary w1nd1ng,.a source of direct current having its positivev pole connected to the mid point ofjsaid primary winding, a vacuum valve havingits anode connected to one end of said primary winding, asecond vacuum valve having its anode connected to the opposite end of said primary winding,

means connecting the cathode of each of said vacuum valves to the negative pole of said source, separate ionizing anodes for each of said valves, a condenser connected inparallel with said first vacuum valve, a condenser connected in parallel with said second vacuum valve and an auxiliary transformer having one winding connected in series with one and means in said cathode connections of said valves to prevent renewed ionization of said valves. a

9. An arrangement for converting direct current into alternating current which comprises a transformer having a primary and a secondary winding, a source of direct current having its positive pole connected to the mid point of said primary winding, a vacuum valve having its anode connected to one end of said primary winding, a second vacuum valve having its anode connected to the oppositeend of said primary winding, means connecting the cathode of each of said vacuum valves to the negative pole of said source, separate ionizing anodes for each of said valves, a condenser connected in par-" allel with said first vacuum valve, a condenser connected in parallel with said second vacuum valve and an auxiliary transformer having one winding connected in :eries with one condenser, another winding connected in series with said other condenser and a third winding connected in series with said source of direct current and adapted on passage of an overload current hrough said third winding to induce a quenching current in each of said condenser circuits for the simultaneous quenching of said vacuum valves, an auxiliary vacuum valve maintained in a conductive state interposed in said common cathode, connection of said vacuum valves, an auxiliary condenser connected in parallel with said auxiliary vacuum valve and a second auxiliary transformer having one winding in series with said source of direct current and another Winding in series with said auxiliary condenser and adapted on increase of the ampere turns of said one winding to induce a quenching current in said auxiliary condenser circuit adapted to quench said aux iliary vacuum valve.

In testimony whereof, I affix my signature.

HARTMANN EGG. 

